It's always tragic when someone dies suddenly. But when such an unexpected event happens to a seemingly healthy child or young adult, it's especially devastating.

While such fatalities are extremely rare, the warning signs and symptoms of sudden cardiac arrest (SCA) can often go undetected for years — and young athletes are especially vulnerable. With the fall sports season in full swing, we turned to Dr. Joseph Marek, a Downers Grove-based cardiologist with Midwest Heart Specialists-Advocate Medical Group and a member of medical advisory board of Parent Heart Watch. The Glencoe-based nonprofit will be holding a fundraiser Saturday at the Chicago Theatre, produced and directed by former ESPN Radio Chicago General Manager Bob Snyder, who lost his 17-year-old daughter to SCA in 2008, while she was playing soccer. For more information, visit sportsradioawards.com or parentheartwatch.org.

Q. What is SCA?

A. Sudden cardiac arrest (SCA) is a condition in which the electrical system of the heart malfunctions, resulting in a disruption of the heart's normal rhythm and loss of its ability to deliver blood to the body. If untreated, this disruption results in sudden death.

Q. How can a heart suddenly cease to function?

A. In an older individual, the most common cause leading to ventricular fibrillation is a blockage in the heart's blood supply. You might get warning symptoms, such as chest pains. But in a younger individual, you might not appear to have any warning signs ... but those who work with youth must be aware (of signs), such as palpitations, fainting or an unexplained shortness of breath.

Q. What causes sudden cardiac arrest and how can it be prevented?

A. Hypertrophic cardiomyopathy — a thickened heart muscle that makes it harder for the heart to pump blood — is the cause of sudden, unexpected cardiac death. An ECG (electrocardiogram) — a simple, noninvasive baseline test that measures the electrical activity of the heart — could probably detect more than 60 percent of those at risk.

Q. So why don't we don't we do more ECGs?

A. It's just not standard practice here. In Europe, it's routine to do it on all young athletes, along with taking a thorough family health history and a physical exam. But in the U.S., we just do the latter two ... but there's a growing number of doctors who think we should be including an ECG.

Q. Why aren't there more?

A. I think there are concerns about cost. But a screening ranges from $30 to $50 in a physician's office. You spend way more than that in preseason shopping at a sports store. I don't think it should be mandatory, but considering that it affects 1 in 50,000-70,000 individuals means it's a lot more common than other things that parents worry about and can befall your child.

Q. Who are some of the athletes who have died from sudden cardiac arrest or had their careers shortened by heart disease?

A. Gaines Adams, a Chicago Bears defensive lineman, had SCA and died Jan. 17, 2010. Cuttino Mobley retired from the NBA after being diagnosed with hypertrophic cardiomyopathy. Jiri Fischer, a hockey player for the Detroit Red Wings, went into cardiac arrest during a game in 2005 and later retired.

Q. I read that you've done over 80,000 screenings? What has turned you into such an advocate?

A. Because these deaths are so devastating to a family and the community, I felt I had a stake in this, not only as a cardiologist but as a parent. This is what prompted me to start our screening program, Young Hearts for Life, in 2006. When you can detect a life-threatening condition before it's too late, that's the payoff. I go to sleep at night feeling a lot better.

Is there a health topic you would like to know more about? Send an email to brubin@tribune.com.